Many self-powered alarm mechanisms exist in homes, buildings, businesses, and are waiting to notify people when a fire has broken out. Most of these devices have been installed many years ago, and over time that may become none functional due to age, insects, dust or being painted by the owner.
One of the major problems that occur with self-powered alarms is that insects make homes in the alarm mechanism. U.S. Pat. Nos. 3,803,527, 3,570,446, 3,552,350 and 2,938,493 separate the mechanically wound mechanism from the ringer, but they all have the potential for insects to enter the area between the striker and the bell mechanism. U.S. Pat. No. 2,999,477 uses a pin welded onto the bell, but the area where the striker is located is subject to insects entering the striker area of the alarm.
The activation mechanism for the alarm can take a variety of similar configurations. In U.S. Pat. Nos. 3,803,527, 2,999,477 and 2,938,493 the activation mechanism is a metallic solder usually made from a eutectic alloy that melts at a specific temperature. When the solder melts, a cap held by the solder is released which in turn releases a keeper pin. The keeper pin restrains the drive mechanism, and when released, the alarm begins to ring. The cap in previous art is made of multiple pieces, which thermally insulate the cap and deflect airflow slowing the temperature reaction. The prior art of the fuse also allows painting over spray to cover the warning portion of the fuse and complicates the manufacturing of the fuse.
Once the alarm has been activated, the alarm will continue to ring until the energy stored in the alarm spring has been exhausted. What is needed is a mechanism that can stop the ringing of the alarm after it has begun and before all of the energy stored in the spring has been exhausted.
Often self-powered alarms need to be inspected to determine if the alarm spring is completely wound. This can be accomplished by inserting a key into the alarm and rotating the key to determine if the spring is fully wound. When this operation needs to be performed, the person performing the inspection must locate a key. None of the prior art provides an obvious key storage location on the alarm so that the inspection can be performed without the inspector providing a special winding key.
While these devices provide a self-powered alarm, they do not completely address potential contamination from insects, allow the fuse to react to temperature changes as quickly as possible, ability to directly halt the alarm spring rotation and provide an obvious location within the housing to store a winding key.